I will have a DIV housing most of the page's content that extends vertically as far as necessary to accommodate the content. At the end of the DIV I want to cap it with a nice rounded-corners bottom.

What is the "right" way to do this?
I was thinking of having another fixed-height div beneath it and centering both, but is that a bad idea? Could some browsers insert a gap between the DIVs and break the continuity?

Thanks.

I was thinking of having another fixed-height div beneath it and centering both, but is that a bad idea?

That is the way I usually do it and is, IMO, the simplest way.

Could some browsers insert a gap between the DIVs and break the continuity?

Not if you make sure that margins and padding are set to 0.

I was thinking of having another fixed-height div beneath it and centering both, but is that a bad idea? Could some browsers insert a gap between the DIVs and break the continuity?

Works for me as well. alpha-1.org.uk (WIP)